Pneumatically operated die-casting machine



p 9 L. A. CATLIN HAL 2,296,907

PNEUMATICALLY OPERATED DIE-CASTING MACHINE Filed Sept. 29, 1941 4 Sheets-Sheet 1 Fi g. l

- fin 0/9 P /4 6364/9 add ea Sept. 29, 1942 A. CATLlN ETAL PNEUMATICALLY OPERATED DIE-CASTING MACHINE 1941 4 Sheets-Sheet. 2'

Filed Sept. 29

Sept. 29, 1942. L. A. CATLIN ETAL 2,296,907

PNEUMATICALLY. OPERATED DIE-CASTING MACHINE Filed Sept. 29, 1941 4 Sheds-Sheet 3 Fig.3

P 71942 L. A. CATLlN ET AL 2,296,907

PNEUMATIGALLY OPERATED DIE-CASTING MACHINE Filed Sept. 29, 1941 4 Sheets-Sheet 4 Patented Sept. 29, 1942 PNEUMATICALLY OPERATED DIE-CASTING MACHINE Leonard Arthur Catlin and Wilfred Henry Cockerill, West Bromwich, England, assignors to E. M. B. Company Limited, West Bromwich, England Application September 29, 1941, Serial No. 412,880 In Great Britain August 1, 1941 7 Claims. (01. 22 ss) This invention relates to pneumatically operated die-casting machines of the kind in which metal, such as zinc or aluminium, or other mouldable material, such as cellulose acetate, is injected in a molten, liquefied or plastic condition between the die parts under the action of compressed air.

In the specification of our patent application No.- 341,978 there is described and claimed means for controlling a die-casting machine, the said means comprising the combination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and means operable by the attendant for controlling flow of air to and from the said cylinder, of a hydraulic locking device for interrupting the movements of the said die head at desired positions, and controlling means therefor.

When the die-casting machine to be controlled is of the kind specified above, it is necessary not only to prevent the molten, liquefied or plastic material from being injected between the die parts while the latter are open, but also to prevent the die parts from being opened while the said material is under air pressure.

To satisfy these conditions the supply of compressed air for effecting the injecting operation is controlled, according to our prior specification aforesaid, by a rotatable shaft which is operable by the attendant only when the die head is in the closed position, and which serves to prevent actuation of a member for controlling the movement of the die head when the shaft occupies any position other than that in which the supply of injecting air is interrupted, the said shaft being provided with its own operating handle.

The object of the present invention is to enable the above mentioned conditions to be satisfied in a simpler and more convenient manner than heretofore.

The invention comprises the combination of a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, valve means for controlling the flow of compressed air to and from the cylinder, additional valve means for controlling the flow of compressed air whereby the material can be injected into the die of the machine, a hydraulic locking device for interrupting the movements of the die head at desired positions, an oscillatory shaft operable by the attendant for controlling the operations of both the first and second mentioned valve means and the hydraulic locking device, and a slidable interlocking rod arranged at right angles to the shaft and responsive to the relative movement between the piston and cylinder whereby movement of the shaft for controlling the second mentioned valve means can only occur when the die head is in the closed position, the said shaft and rod being adapted to co-operate with each other to limit the extent of the movement that can be imparted to the said shaft by the attendant when the die head is in the open position.

In the accompanying sheets of explanatory drawings:

Figure 1 is a sectional front elevation, Figure 2 a plan, and Figure 3 a part sectional rear elevation, of means constructed in accordance With the invention for controlling a die-casting machine of the kind specified.

Figure 4 is a fragmentary front view illustrating the various positions to which the controlling member is movable by the attendant.

Figure 5 is a fragmentary sectional view taken on the line 5-5 of Figure 4.

In carrying the invention into effect as shown, we employ for actuating the movable die-head a of the machine a piston b which is slidable in a horizontal cylinder 0 under the action of compressed air, and which is secured on a rod (1. On the rear side of the cylinder 0 are mounted two pairs of spring-loaded valves 1, g. The valves 1 serve to admit to opposite ends of the cylinder 0, compressed air for actuating the piston 12, and the valves g serve to release air from opposite ends of the cylinder.

Arranged coaxially with and secured to one end of the air cylinder 0 is a second cylinder h, and slidable in the second cylinder is a second piston i on the piston rod d, the latter being arranged to pass through a gland 9' between the adjacent ends of the two cylinders and another gland k at the other end of the second cylinder. At each end of its upper side the second cylinder h is provided with an opening 172 leading to an oil or other liquid container n on the upper side of this cylinder, the latter being filled With oil at both sides of its piston z. The openings m are controlled by a pair of vertically slidable poppet valves 0, and these valves are loaded by springs 11) which tend to hold the valves in closed positions for interrupting communication between the liquid cylinder h and container n.

At its outer end the piston rod d is connected by 'a vertical pivot pin q to pivotal links 1 forming part of a toggle linkage through which motion can be imparted from the piston rod to the die head a.

The other part of this linkage is formed by pivotal link s which are pivotally interconnected in pairs, and which at their junctions are connected to the adjacent ends of the first mentioned links r, the opposite ends of each of the said pairs of links being connected to the die head a and a fixed anchorage 15 respectively. The anchorages t are formed or provided on a housing it which is secured to the end of the liquid cylinder h remote from the air cylinder 0, and which serves as a protective cover for the outer end of the piston rod 11 and the adjacent parts of the toggle linkage 1', s, the die head a being slidably supported by fixed horizontal guides 22 which at one end are secured to the said housing. In Figure 2 the die head a is shown in full lines in one extreme position and in broken lines in the other extreme position.

On the rear side of the housing u are mounted two pairs of spring-loaded valves w, w, for controlling the supply of air to and from a pneumatically operable and relatively slidable piston and cylinder whereby the molten metal or other material to be cast is injected into the die of the machine. As this piston and cylinder (herein termed the injecting piston and cylinder) are of known form and constitute no part of the present invention, they are not illustrated in the drawings. The valves 11) serve to admit compressed air to opposite ends of the injecting cylinder, and the valves :10 serve to release air from opposite ends of this cylinder.

For actuating the air valves f, 9, associated with the air cylinder we employ two pairs of cams y on a horizontal shaft 2, the latter being rotatably supported by bearings 2 on the rear sides of the air cylinder and the housing u abovementioned. This cam shaft 2 also carries another pair of cams 3 for actuating the air valves w, cc, associated with the injecting cylinder. Also the cam shaft 2 is connected by bevel gearing 4 to a transverse operating shaft 5 which extends through an aperture in and is rotatably supported by a projection 6 on the under-side of the liquid cylinder 71. The operating shaft 5 is connected by a link and lever mechanism 1 to a second cam shaft 8 which extends transversely across and is rotatably supported by the liquid container n on the upper side of the liquid cylinder h. The second cam shaft 8 carries cams 9 for actuating the liquid valves 0 associated with the liquid cylinder h, these cams being adapted to act on the adjacent ends of a pair of rockers 9 which are mounted on parallel axes within the liquid container n, and which at their other ends are adapted to act on the liquid valves.

Mounted on the front end of the operating shaft 5 is a hand lever it] through the agency of which the operating shaft can be oscillated by an attendant for actuating the air valves f, g, and w, :12, and the liquid valves 0-. The hand lever IE] is formed or provided at its lower end with a pair of abutments l2, l3 arranged in different vertical planes, and at a position adjacent to this end is pivotally connected by a pin Hi to a slotted member l I on the front end of the operating shaft 5, so that the lever is capable of pivotal movement in a plane containing the axis of the operating shaft. Another pair of abutments I5, l5 are adapted to co-operate with the lever abutments l2, !3 for actuating the lever I!) in the manner hereinafter described. The abutments l5, l6 are adjustably mounted in spaced relationship and in different vertical planes on rods ll which are connected at one end to the die head a, and which are slidably supported near the other end by a fixed bracket l8. Normally the lever abutments i2, 13 are situated in the paths of the corresponding abutments l5, l6 as shown in full lines in Figure 5, but they can be moved out of these paths by appropriate movement of the lever lil about its pivot axis in a forward direction.

For limiting the amount of angular movement that can be imparted to the operating shaft 5 when the die head a is in the open position we arrange in association with the underside of this shaft an interlocking member IS in the form of a slidably mounted horizontal rod which is situated at right angles to the shaft and is responsive to the movement of the die head a. One end of this rod 19 is attached to the lower end of the pivot pin q which connects the piston rod (1 to the toggle linkage r, s, and the other end of the rod is slidably supported at a position beneath the operating shaft in another aperture formed in the projection 6 on the underside of the liquid cylinder h. The part of the rod 19 adapted to slide through the projection 6 has its upper side cut away or otherwise shaped to provide a pair of horizontal flats 23), 2| situated end to end at different levels, the lowermost fiat (2|) being situated nearest to the end of the rod remote from the die head a. Also the part of the operating shaft 5 situated adjacent to the interlocking rod I3 is cut away or otherwise shaped to provide a pair of oppositely inclined flats 23 and a curved portion between the adjacent ends of these flats as shown. Moreover the arrangement is such that when the die head a is in the open position the flat 2'0 on the interlocking rod I9 is situated beneath the operating shaft 5 and angular movement of the latter in either direction is limited by contact of one of the flats 23 on the shaft with the flat 20 on the interlocking rod, but when the die head is in the closed position the flat 2| on the rod is situated beneath the operating shaft and angular move ment of the latter is unobstructed by the rod.

In the initial position of the parts above described the die head a is in the open position shown in full lines in the drawings, the hand lever I0 is in the central or idle position shown in full lines in Figure 4, and the valves f, 0, w, as, are closed. Also the fiat 20 on the interlocking rod I9 is situated beneath the operating shaft 5. To impart a forward or die-closing movement to the head a, the hand lever I0 is moved in a counter-clockwise direction to the position 15 shown in the broken lines in Figure 4, the extent of this movement being determined by contact of one of the flats 23 on the operating shaft 5 with the fiat 25] on the interlocking rod l9. As a further precautionary measure we also prefer to provide on the front of the liquid cylinder h a fixed stop 24 against which the lever I!) can abut at the end of the movement above mentioned, and which serves to minimize wearing of the flats 2e, 23 by hard usage. If the lever I0 is now pulled forwards it can be caused to assume a position in which its further movement in a counter-clockwise direction is unobstructed by the stop 24, but such further movement is still prevented by contact of the above mentioned fiat 23 on the operating shaft 5 with the flat 20 on the interlocking rod [9. During the movement of the lever It! from its idle position to the position at it passes another position lEi also shown in broken lines in Figure 4. The movement of the lever between its idle position and the position it causes one pair of the cams y to open the appropriate valves f, a, for admitting compressed air to the outer end of the cylinder 0, and releasing air from the inner end of this cylinder. The piston 17, however, cannot be moved by the action of the compressed air until the valves associated with the liquid cylinder 'h are opened, this being eiTected by the cams 9 during the movement of the lever In from the position [0 to the position It). When the lever l0 reaches the latter position the piston 1) commences to move the die head a towards the closed position, and this movement continues until the abutment l comes into contact with the lever abutment I2 and, by acting on the latter, returns the lever to the position l0 for re-closing the valves 0 associated with the liquid cylinder h. The closing of these valves 0 interrupts the flow of liquid between the cylinder h and the container n, and thereby prevents further movement of the piston i, the liquid in the cylinder serving as a hydraulic lock. Consequently the movement of the air piston b and the die head a is interrupted. For enabling the piston b and die head a to continue their movement, the hand lever It] is pulled forwards against the action of a return spring 25 (Figure 5) and returned to the position It before being released, the forward movement of the lever causing it to move about its pivot axis into a position in which the lever abutments l2, 13 are out of the paths of the movable abutments l5, It, as shown in Figure 5. The die head a is now moved by the piston b to its closed position as shown in broken lines in the drawings. When the die head a reaches its closed position the flat 2| on the interlocking rod i9 is situated beneath the operating shaft 5, and by pulling the lever in forwards until it is unobstructed by the stop 24 the lever can be moved still further in a counter-clockwise direction to the position I 60. During this further movement of the lever l0, which cannot take place unless the die head a is in its closed position, one of the cams 3 opens the corresponding air valves w, :r for causing the injecting piston above-mentioned to move in the direction for injecting the molten metal or other material into the die.

When it is required to return the die head a to its open position, the hand lever I0 is pulled forward and moved in a clockwise direction past the central or idle position to the position l0 shown in broken lines in Figure 4. During the first part of this clockwise movement of the lever I i] the previously actuated air Valves w, 3:, are released and the others of these valves are actuated by the corresponding cam 3 for causing the injecting piston to be returned. In moving from the central or idle position to the position Hi the lever IE! moves past another position 10 The movement of the lever between the idle position and the position Ill causes the other pair of the cams y to open the appropriate valves f, g, for admitting compressed air to the inner end of the cylinder 0, and releasing air from the outer end of this cylinder. But the piston b cannot be moved by the action of the compressed air until the valves 0 associated with the liquid cylinder it have been opened, this being eifected during the movement of the lever H] from the position I 0 to the position Hi During the return movement of the die head a the abutment I6 coacts with the lever abutment I3 to return the lever IE to the position I0 for interrupting the movement of the die head, the lever being subsequently pulled forwards as above described and again moved to the position Hi for enabling the return movement of the head to be completed by the action of the compressed air on the piston 17. By suitably adjusting the positions of the abutments IS, IS on the rods I! the movements of the die head a can be interrupted at any desired positions for enabling cores to be inserted into or withdrawn from the die. Moreover, the abutments I5, Hi can be moved to inoperative positions when this is required.

By this invention we are able not only to satisfy the required conditions in a very simple and convenient manner, but also to provide controlling means of robust and compact form for diecasting machines of the kind specified.

The invention is not limited to the example above described as subordinate details may be varied as required.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

l. Controlling means for a die-casting machine of the kind specified, comprising the combination of a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, valve means for controlling the flow of compressed air to and from the cylinder, additional valve means for controlling the flow of compressed air whereby the material can be injected into the die of the machine, a hydraulic locking device for interrupting the movements of the die head at desired positions, an oscillatory shaft operable by the attendant for controlling the operations of both the first and second mentioned valve means and the hydraulic locking device, and a slidable interlocking rod arranged at right angles to the shaft and responsive to the relative movement between the piston and cylinder whereby movement of the shaft for controlling the second mentioned valve means can only occur when the die head is in the closed position, the said shaft and rod being adapted to co-operate with each other to limit the extent of the movement that can be imparted to the said shaft by the attendant when the die head is in the open position.

2. Means as claimed in claim 1, in which the shaft and rod are formed with flats which cooperate with each other to limit the extent of the movement that can be imparted to the said shaft by the attendant when the die head is in the open position.

3. Means as claimed in claim 1, in which the shaft and rod are formed with flats which cooperate with each other to limit the extent of the movement that can be imparted to the said shaft when the die head is in the open position, the said rod being formed with another fiat for enabling further movement of the shaft to be effected when the die head is in the closed position.

4. Means as claimed in claim 1 and having in combination, toggle linkage through which the die head is movable by the relative movement between the piston and cylinder, and means whereby the said movement is imparted directly to the interlocking rod.

5. Means as claimed in claim 1 and having in combination a rod. on which the piston is mounted and which is movable by the piston, toggle linkage through which the die head is movable by the piston rod, and means connecting the piston rod to the interlocking rod.

6. Means as claimed in claim 1 and having in combination a rod on which the piston is mounted, and which is movable by the piston, toggle linkage through Which the die head is movable by the piston rod, and a pin connecting both the toggle linkage and interlocking rod to the piston rod.

'7. Means as claimed in claim 1 and having in combination with the oscillatory shaft, a cam shaft, cams on the shaft for actuating both of the valve means, a second cam shaft, cams on the second shaft for controlling the operation of the hydraulic locking device, gearing interconnecting the oscillatory shaft and the first mentioned cam shaft, and link and lever mechanism interconnecting the oscillatory shaft and. the second mentioned cam shaft.

LEONARD ARTHUR CATLIN.

WILFRED HENRY COCKERILL. 

